1. Field of the Invention
The invention relates to a device for filleting beheaded fish which are fed to a filleting apparatus in their swimming position and includes at least one tool comprising at least one circular knife for cutting free the belly spokes or radii as well as guides for supporting the belly of the fish.
2. Prior Art
When filleting fish by means of the aforementioned device the fish to be filleted is normally placed onto a feeding conveyor either manually or automatically, the feeding conveyor performing the feeding into the filleting machine. In this context it is of great importance with regard to the quality of the product to be achieved as well as to the performance and the effectiveness of the working process that the fish are guided through the machine in a specifically determined position independent of the differing fish sizes. This concerns the level of its vertebral column as well as the alignment of its plane of symmetry. While the latter can be achieved via the outer contour of the fish by lateral supports and guides synchronised with respect to their central position, the level of the vertebral column can only be controlled by orientation of the vertebral column itself.
A filleting machine can be taken from German Pat. No. 1 063 784 in which the beheaded fish to be processed are pushed onto a spike with their cutting surface leading, a belly slitting knife entering into their lower sides. After passing a belly flap cutter the fish thus opened at its belly cavity reaches the working area of a bone cutter whose effective cutting edges are only set free after arrival of the belly cavity end in order to avoid a cutting into the vertebrae namely the lateral vertebral appendages of the spinal column.
With this device only species of fish whose belly cavities run bow-shaped to the anus in their upper boundaries so that the spike can glide along this upper boundary and leave the belly cavity without damaging the muscle flesh can be processed. Fish belonging to the Gadide species, e.g. cod, pollack, coalfish, haddock cannot be processed in this way since their belly cavities end in a bag-shaped part placed behind the anus. Furthermore it has been apparent that the processing of fish with an extremely short belly cavity, as can be found especially in fish with high backs, cannot be accomplished reliably since the effective cutting edges of the knives must be set free early enough so that the leading end of the vertebral column is not yet supported by the guides following the knives. Thereby a cutting into the lateral vertebral appendages resp. the vertebrae occurs which leads to friction between the fish and the conveyor due to the high cutting resistance and causes damage to the fish body. Finally, with respect to constructional necessities and the costs incurred it is a disadvantage that separate tools are provided to open the belly cavity and to cut free the belly radii, respectively, the tools also having to be controlled.
3. Object of the Invention
It is therefore the main and essential object of the invention to provide a filleting device which can be manufactured at low cost and used for processable fish species independent of the size of the fish.